As application of mobile devices, such as cell phones, in social life grows more comprehensive, frequency in use of the mobile devices is increasing more and more. However, when a user holds a cell phone in his or her hand for a long time, the user feels a burden. Especially, using of the mobile device in a specific pace or using a smart phone navigation during driving may bring danger with the user because the user cannot freely use his or her two hands. Moreover, as mobile phone operating systems and touch screen technology advance more and more, users feel difficulty in manipulating their mobile phones with one hand due to an increase of a screen size. In the case of women with small hands or persons who use mobile phones before going to bed, they may easily drop their phones because it is difficult to manipulate the phones with one hand.
However, there is no effective method of solution on the above-mentioned problems till now.